Climate Change Is Not Producing More Tornadoes

Was the deadly EF-5 tornado that ripped through Moore, Okla. and killed 24 the result of climate change?

Weather Underground meteorologist Jeff Masters says probably not.

While the changing climate does influence weather in countless ways, these systems are so complex we can't blame one natural disaster directly on global warming. When it comes to tornadoes, climate changes doesn't seem to be a big player, yet.

There's been no change in wind shear — abrupt changes in wind patterns — during the decades scientists now associate with man-made climate alterations (basically the last 40+ years).

Wind shear often translates into tornadoes forming. The number of reported tornadoes has gone up over the climate change period, but only because of better monitoring and greater awareness, Masters says.

However, according to a model from Purdue University scientist Robert Trapp, there will be more severe thunderstorm days in the future — though they'll mostly be concentrated on the East Coast.

It does not appear that there has been an increase in U.S. tornadoes stronger than EF-0 in recent decades, but climate change appears to be causing more extreme years — both high and low — of late.

Tornado researcher Dr. Harold Brooks of the National Severe Storms Laboratory in Norman, Oklahoma said in a 2013 interview on Andrew Revkin's New York Times dotearth blog: "there's evidence to suggest that we have seen an increase in the variability of tornado occurrence in the U.S."

Preliminary research using climate models suggests that we may see an increase in the number of severe thunderstorms capable of producing tornadoes over the U.S. late this century, but these thunderstorms will be more likely to produce damaging straight-line winds, and less likely to produce tornadoes and large hail.